Silver nanoparticles induce a non-immunogenic tumor cell death.

Immunogenic cell death (ICD) is a form of cell death characterized by the release of danger signals required to trigger an adaptive immune response against tumor-associated antigens. Silver nanoparticles (AgNP) display anti-proliferative and cytotoxic effects in tumor cells, but it has not been previously studied whether AgNP act as an ICD inductor. The present study evaluated the in vitro release of calreticulin as a damage-associated molecular pattern (DAMP) associated with the cytotoxicity of AgNP and their in vivo anti-cancer effects. In vitro, mouse CT26 colon carcinoma and MCA205 fibrosarcoma cells were exposed to AgNP and then cell proliferation, adhesion, and release of calreticulin were determined. The results indicated there were time- and concentration-related anti-proliferative effects of AgNP in both the CT26 and MCA205 lines. Concurrently, changes in cell adhesion were detected mainly in the CT26 cells. Regarding DAMP detection, a significant increase in calreticulin was observed only in CT26 cells treated with doxorubicin and AgNP; however, no differences were found in the MCA205 cells. In vivo, the survival and growth of subcutaneous tumors were monitored after vaccination of mice with cell debris from tumor cells treated with AgNP or after intra-tumoral administration of AgNP to established tumors. Consequently, anti-tumoral prophylactic immunization with AgNP-dead cells failed to protect mice from tumor re-challenge; intra-tumor injection of AgNP did not induce a significant effect. In conclusion, there was a noticeable anti-tumoral effect of AgNP in vitro in both CT26 and MCA205 cell lines, accompanied by the release of calreticulin in CT26 cells. In vivo, immunization with cell debris derived from AgNP-treated tumor cells failed to induce a protective immune response in the cancer model mice. Clearly, further research is needed to determine if one could combine AgNP with other ICD inducers to improve the anti-tumor effect of these nanoparticles in vivo.

What is Currently Known about Odontogenic Keratocysts?

PURPOSE: To present updated information on odontogenic keratocyst (OKC) classification, etiology, genetic and molecular alterations, epidemiology, clinical presentation, radiographic characteristics, histological and immune histochemical features, differential diagnosis, treatment, and controversies, as well as a literature review of case frequencies in different countries. MATERIALS AND METHODS: Studies were selected using the key words 'odontogenic keratocyst,' 'odontogenic cysts,' 'odontogenic keratocyst and clinical study'. Full-text papers were reviewed on the basis of the inclusion and exclusion criteria. The literature search aimed to find articles that would show the frequency of OKC, dentigerous cyst, radicular cyst, and other cysts. RESULTS: OKC presents local aggression and high recurrence; therefore, a better understanding of its clinical characteristics and the genetic and molecular factors involved in this peculiar and controversial lesion is required. It is always essential to discuss treatment alternatives. Although OKC is an entity with a high recurrence, aggressive treatment is not advisable in all cases because factors such as commitment to anatomical structures and possible complications should be considered. However, periodic radiographic controls are advised. CONCLUSION: To reduce the high number of present cases worldwide, it is important to improve knowledge on this pathology so that accurate diagnoses can be achieved and appropriate treatment can be provided. OKC presents local aggression and high recurrence; therefore, a better understanding is needed of the clinical characteristics and genetic and molecular factors involved in OKC. Furthermore, it is always essential to discuss treatment alternatives.